Evaluation of a standard shade guide for color change after disinfection.

OBJECTIVE: To determine if surface disinfectants cause a change in the shade perception of a standard Classic Vitapan shade guide. METHOD AND MATERIALS: Consistency in shade selection for dental restorations involves many factors, and one of the most important is the shade tabs used in the selection process. Ten shade tabs each of shades B2, D2, C1, and A3.5 were selected from the Classic Vitapan shade guide (Vident). All tabs were measured with the EasyShade shade device (Vident) at baseline. Three tabs of each shade were set aside as controls. The other 7 tabs of each shade were treated with the surface disinfectant Cavicide (Metrex Research) for 480 cycles to simulate a year's usage. After each 480 cycles, all the tabs were again measured with the EasyShade. This process was repeated to simulate 2 and 3 years of use. RESULTS: The data were analyzed to calculate the delta E 2000 for any change. A statistically significant increase was observed in the value (L*) and chroma (C*) after 2 and 3 years of simulated treatments. These changes were not perceptible to the clinician. CONCLUSIONS: The authors suggest that 1 standard shade guide be set aside to compare against those in clinical use to determine when they should be replaced.

Sensitivity and tooth whitening agents.

PURPOSE: Three commercially available dentist-prescribed home-applied bleaching systems were evaluated to identify the incidence of sensitivity and to compare the efficacy of whitening the maxillary anterior teeth of 18 patients. METHODS: NiteWhite Excel 2Z (Discus Dental), fx (Challenge Products), and Rembrandt Xtra-Comfort (DenMat Corp.) were randomly assigned to six patients each. The fx product was used as a control since it was not advertised as a zero sensitivity product. The manufacturers' instructions for tray fabrication and use were followed while the patients bleached for 2 weeks. The patients kept a diary and were recalled at 1 week, 2 weeks, and 4 weeks. The shade change and the presence or absence of any sensitivity were evaluated at each recall. RESULTS: NiteWhite Excel 2Z was used for 83 days of treatment with the following percentage of positive sensitivity reported: 0% hot and cold, 2.4% throat sensitivity, 2.4% tongue sensitivity, and 25.3% gingival sensitivity. Rembrandt Xtra-Comfort was used for 84 days with 0% hot and cold, 0% throat, 11.9% tongue, and 27.4% gingival sensitivity reported. The fx product was used for 83 days and resulted in 14.5% hot and cold, 3.6% throat, 1.2% tongue, and 16.9% gingival sensitivity. All products lightened the teeth an average of eight shade tabs on the Vita guide. There was a statistically significant difference between the groups when comparing the presence of sensitivity (chi-squared test, p < .001) but not when comparing the shade tab change. CLINICAL SIGNIFICANCE: Of the products tested, all produced similar change in shade tab value, none were sensitivity free, but NiteWhite Excel 2Z and Rembrandt Xtra-Comfort did not produce thermal sensitivity.